1. Field of the Invention
This invention relates to an image displaying method and device, wherein image information is displayed in accordance with an alteration in optical characteristics, which alteration is caused to occur by voltage application performed in accordance with the image information. This invention particularly relates to an improvement in a technique for the voltage application. This invention also relates to an image displaying control method and apparatus.
2. Description of the Related Art
As image displaying devices referred to as electronic paper, image displaying devices utilizing various displaying techniques have heretofore been proposed.
As the displaying techniques for the image displaying devices, for example, there have been proposed the displaying techniques, wherein image information is displayed in accordance with an alteration in optical characteristics, which alteration is caused to occur by voltage application performed in accordance with the image information. As the image displaying devices utilizing the displaying techniques described above, for example, there have been proposed micro-capsule types of electro-migration display devices provided with a dispersion layer, in which micro-capsules containing positively charged white particles and negatively charged black particles have been dispersed. With the micro-capsule types of electro-migration display devices, the white particles and the black particles are caused to migrate within each of the micro-capsules by voltage application performed in accordance with image information, and the image information is thereby displayed. As the image displaying devices utilizing the displaying techniques described above, there have also been proposed polymer network liquid crystal display devices provided with a liquid crystal layer, which has been prepared with a process, wherein a liquid crystal and an acrylic monomer are encapsulated within a cell, and wherein UV light is irradiated to the cell in order to form a polymer network within the liquid crystal. With the polymer network liquid crystal display devices, orientations of major axis directions of liquid crystal molecules are altered in accordance with voltage application, and image information is thereby displayed.
Examples of the techniques for applying the voltage to the dispersion layer or the liquid crystal layer in the image displaying devices described above include a passive technique for applying the voltage by use of a simple matrix electrodes and an active actuation technique for applying the voltage by use of thin-film transistors (TFT's). (The passive technique and the active actuation technique are described in, for example, “Color Liquid Crystal Display” Hiroo Hori and Koji Suzuki, Kyoritsu Shuppan, pp. 73-140, June 2001.)
However, with the passive technique utilizing the simple matrix electrodes described above, the problems are encountered in that, in cases where the number of pixels constituting the displayed image becomes large, contrast becomes low due to cross talk. Therefore, with the passive technique utilizing the simple matrix electrodes described above, it is not always possible to display image information of a large area and a high definition, such as the image information of electronic newspapers and electronic maps.
Also, with the active actuation technique utilizing the TFT's described above, since the actuation voltage is limited to at most approximately ±15V, it is not always possible to perform a quick alteration in optical characteristics of the dispersion layer or the liquid crystal layer with the low voltage described above. Further, the active actuation technique utilizing the TFT's described above has the problems in that the cost of the TFT boards is not capable of being kept low.